fix (n.)

"position from which it is difficult to move," 1809, American English, from fix (v.). Meaning "dose of narcotic" is from 1934, shortened from fix-up (1867, originally in reference to liquor). Meaning "reliable indication of the position of a ship, plane, etc." (by reference to fixed positions) is from 1902.

Sense of "fasten, attach" is c. 1400; that of "to make (colors, etc.) fast or permanent" is from 1660s. The meaning "settle, assign" evolved into "adjust, arrange" (1660s), then "repair" (1737). Sense of "tamper with" (a fight, a jury, etc.) is from 1790. As euphemism for "castrate a pet" it dates from 1930. Related: Fixed; fixing.